MEDICAL ENTOMOLOGY

1. Presenter: Insha Jan

2. THE ORIGIN OF THE WORD ENTOMOLOGY
The word entomology derived from Greek entomom (= insect), logia (=logy)

3. Definition: Entomology
• Science that deals with the study of arthropods in general, and incorporates
sciences like zoology, biology, parasitology and microbiology.
MEDICAL ENTOMOLOGY

4. • Medical Entomology
• Branch of entomology which deals with arthropods which affect the health
and well-being of man and vertebrate animals.
• Medical entomology is the medical science directly concerned with vectors
that affect human and animal health.

5. Vectors
 Vectors are mostly insects which carry and transmit disease agents from
patient to healthy person; or from disease sources to uninfected food or
drinks

6. • Arthropods have incredibly diverse morphological, physiological, and
behavioral adaptations to their surroundings which makes the study of
arthropods an exciting subject.

7. • Despite their small size, the sheer numbers or biomass of insects means that
they have a significant impact on the environment and therefore upon our
lives.
• Although most arthropods have never adapted to a truly marine
environment, they inhibit almost all terrestrial and aquatic environments.
Some have adapted to live with us (cockroches) while others live on us
(lice).

8. ARTHROPODS
• “Arthropod” is derived from Greek word ( Arthron : jointed , pod: leg)
JOINTED LEG

9.  Multicellular animal (metazoa)
 Bilaterally symmetrical
 Body covered with exoskeleton
 Segmented body – that allows movement
 Jointed limbs and jointed mouthparts – that allow
 extensive specialization
 Ventral ladder type of nervous system
 Growth by molting, which is controlled by hormones

10. - Divided into 5 classes
I. Class Insecta --- Medically important insect :
* Order Diptera (house fly tse tse fly)
* Order Anoplura (lice)
* Order Hemiptera (bed bugs)
* Order Siphonaptera (Fleas)
II. Class Arachnida
III. Class Crustacea
IV. Class Chilopoda
V. Class Diplopoda

11. • Such as mosquitoes , house fly and cockroaches all have
• 3 body segments- Head, thorax and abdomen.
• Head :
• Eyes, one pair of antennae & three pairs of appendages developed as mouth
parts
• Thorax :
• Three pairs of legs, & one or two pairs of wings in most insects.
• Abdomen :
• Segmented with the end (posterior) part serving to show the sex of the insect.

12. • Include centipedes,
• Many body segments
• 1 pair legs / body segment
• 1 pair antennae
• Poison jaws

13. • Include millipedes , all possess
• Many body segments
• 2 pair legs / body segment
• 1 pair antennae

14. • Includes lobsters, crabs, cray fish
• Their features are:
• Varied number of body segments – usually there is a head , thorax , and
abdomen but there is much fusion , reduction and modification of segments
• Varied no. of legs
• 2 pair antennae

15. • Spiders, mites, ticks, scorpions. They all have
• 2 body segments – cephalothorax and abdoman
• 8 legs
• No antennae

16. Metamorphosis
 Morphological changes and development in the life cycle of Arthropods
Two types of metamorphosis:
 Complete Metamorphosis
 Incomplete metamorphosis

17. Complete Metamorphosis
 Insects which undergo complete
metamorphosis ( ex: flies) have four
stages of development :
 Eggs - Larva - pupa – Adults

18. Incomplete Metamorphosis
 Insects which undergo incomplete
metamorphosis ( ex. Bugs ) have
three stages of development :
Eggs/ova - nymph – Adults

19. • Role as vector
Insects may act as
 Vector/transmitter of disease agents
 As direct cause/etiology of disease or injury

20. Two modes of transmission
 As mechanical vector
 As biological vector

21. Role as mechanical vector
 Disease agents do not develop or multiply inside the vector
 Example : gastroenteritis agents in flies and cockroach
 Transmission occurs through the proboscis, legs, body, wings

22. Role as biological vector
- Disease agents develop or multiply inside the vector
- Example :Plasmodium sp. Anopheles sp.
- Transmission occurs through the proboscis

23. • Role as vector
Anopheles , vector of malaria

24. • Role as the cause of disease
Disease or injury may be caused by insects through various means :
- Mechanical injury
- Injection of poisonous substances
- Allergies
- Psychosis

25. • Role as the cause of disease
Mechanical cause
 Bites - sting and bloodsucking - larval movement
 Arthropods may act as :
 Endoparasites : larva of flies causing myiasis
 Ectoparasites: headlouse
 Permanent parasites : fleas
 Intermittent parasites: mosquito

26. Injection of Toxic substance
 Poison enters through :
 Direct contact (caterpillars), bites (spider), sting (scorpion), piercing
(mosquito)
 Common symptoms :
 Itching, swelling, urticaria (mosquito, caterpillars)
 Hemolysis (scorpion)
 bleeding (bees)
 Nerve damage (scorpion)
Allergies
 Dyspnea /asthma : caterpillar, butterflies
Psychosis
 Entomophobia
A boy with allergy
from mosquito bite

27. • Insect as cause of injury and disease
Scorpion Spider

28. Life cycle
Mosquito
 Life span: 2 weeks
 Complete Metamorphosis (eggs - larva - pupa - adults).
 Eggs laid on water surface :
– White 1-2 hours - Turns black 2-4 days - Larva ( stage I - IV) 6-8 days -
Pupa 1-3 day - Adults male and female

29. 1. Mosquito bites may cause urticaria, and dermatitis
2. As vector transmitter of many diseases :
Example 1:
Malaria (Plasmodium)
 Main vectors of malaria in Jawa and Bali : Anopheles sundaicus, A.
aconitus, A. subpictus, A. maculatus, A. balabacensis, A. sinensis.

30.  Vector of disease : Example 4 & 5
Yellow fever - by Yellow Fever virus
 Primary vectors : Aedes aegypti, Ae. simpsoni
Japanese B. encephalitis and St. Louis encephalitis (by JBE and SLE
virus)
 Primary vectors : Culex pipiens, C. tarsalis, Ae. togoi

31. Medical importance
Aedes aegypti , vector of dengue fever

32. Family Psychodidae
Genus Phlebotomus = Sandflies1
Family Simuliidae
Genus Simulium = black fly = buffalo gnats
2
Family Ceratopogonidae/Heleidae
Genus Culicoides = midges = punkies
3
Bloodsucking Flies
Flies

33. Family Tabanidae
Genus Tabanus = horse fly
Genus Chrysops = deer fly
Genus Hybomitra4
5
Family Muscidae
Genus Glossina = Tsetse Flies
Genus Stomoxys = Stable Flies
Bloodsucking Flies

34. Medical importance
 The bites may cause dermal papules, intense pain, itching, nausea,
fever
 As vector of the following diseases :
Flies
Phlebotomus fever = demam papataci
Disebabkan virus
Terdapat di laut Tengah, Arab, Asia selatan
vectornya Phlebotomus papataci
Bartonellosis
Disebabkan Bartonella baciliformis
Terdapat di Pegunungan Andes
vectornya Phlebotomus verrucosum
Kala azar
 By Leishmania donovani
Oriental sore
By Leishmania tropica
American Leishmaniasis
 By Leishmania braziliensis
Phlebotomus sp.

35. Medical importance
 Painful bite, causing itch and fever
 Act as vector of disease (as intermediate host of Filarial worm) :
 Culicoides grahami, and C. austeni, as vector of Acanthocheilonema
perstans
 Culicoides grahami as vector of Dipetalonema streptocerca
Culicoides sp.

36. Culicoides sp.
Source : Color Atlas of Medicine and parasitesology. 1977
W. Peters & H.M. Gillers
Adults Culicoides sp.

37. Flies
Medical importance
 African sleeping disease
 Trypanosoma gambiense, vector is Glossina palpalis

38. Stomoxys sp.
Medical importance
 Painful bites; mostly on cattle and horses which may cause anemia
 Mechanical vector of :
Trypanosoma evansi – which causes a disease in animals called surra
- Example: Stomoxys calcitrans

40. Non-biting Flies
Family Muscidae
– Musca domestica = House flies1
Family Sarcophagidae
– Meat flies
– Characteristic : viviparous
– Lay its larva on meat
Example :
– Genus Sarcophaga : myiasis semi-systemic and
accidental
– Genus Wohlfahrtia : specific
– myiasis
2

41. Non-biting Flies
Family Calliphoridae
– Blow flies
– Example : Chrysomyia bezziana
– Specific Myiasis on open wound, nostril, ear
holes (myiasis of the skin and atrial openings)3
Family Drosophilidae
– Species: Drosophila melanogaster
– Also called fruit flies, may cause accidental
intestinal myiasis4

42. Musca domestica
Medical importance
 Adult flies may act as mechanical vector of many
disease agents : protozoa, worm eggs, bacteria,
virus.
 Larva stage may invade human tissue causing a
disease called myiasis
Lalat rumah

43. Musca domestica
Musca domestica (House flies )

44.  Classified under ordor Acarina
 Causing acariasis
 Medically most important mites :
 Family Sarcoptidae (Scabies mite)

45.  Etiology : Sarcoptes scabiei
 Family Sarcoptidae
 Order : Acarina
 Disease : scabies, sarcoptic
mange
 Ectoparasite, inhabit the
skin creating tunnels under
the stratum corneum
where female lay eggs
 Predilection sites : thin skin
folds (between fingers,
armpit, wrist, genital fold)
Source :A Colour Atlas of Clinical Parasitology. Tomio Yamaguchi.
Translation : Lesmana Padmasutra, dkk.

46.  Common among children and adults of poor personal hygiene
 Among inhabitants of prisons, orphanages, boarding houses and
military barracks
Source :A Colour Atlas of Clinical Parasitology. Tomio Yamaguchi. Translation : Lesmana Padmasutra, dkk.

47. • Environmental control
• Chemical control
• Biological control
• Genetic control
• Newer methods

48.  Environment control
 Elimination of breeding
places
 Filling and drainage
operation
 Proper disposal of refuse
& water management

49. Chemical control
Use of insecticides like dichlorophenyltrichloroethane (DDT), baygon and
pyrethrum flowers, and arsenical compounds.

50. Biological control
• Use of specific viruses, bacteria,
protozoa, fungi which are pathogenic to
various morphological forms of
arthropods
• Use of Gambusia fish that feed on larvae
of mosquitoes.
• Barbell fish and Gambusia fish have
been successfully used for control of
Cyclops.

51. • Genetic control
• Sterile male technique
• Chromosomal translocations
• Cytoplasmic incompatibility
• Newer methods
• Insect growth regulator
• (Adulticide)
• Chemosterilants
• (Chemical compound causes reproductive sterility)

52. •